network/avahi: Updated README with gtk-sharp dep.
network/avahi: Updated README with gtk-sharp dep.

  Thanks to chrisabel on #SlackBuilds irc.

Signed-off-by: dsomero <dae8ac18105ddd758ba5f28feddefd6acb687160@slackbuilds.org>

panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds